Zong, which provides mobile payments for many Facebook app developers and the partner for the upcoming Credits system has raised $15 million according to Inside Social Games. Echovox, the parent company has been supporting the venture for three years and this is the furst time the company has had investment funding.

Zong’s rival, Boku raised $25 million back in January and is showing stiff competition for Zong. Zong’s CEO David Marcus commented on the funding: “We’ve been growing like crazy in the past couple quarters, and we need to hire more people in all of our departments.”

Zong’s strongest point is their use of mobile phones to purchase the currency. The charges are made in seconds using codes sent to the phone and appear on a regular phone bill for added convenience. Marcus believes this is a huge advantage that Zong has over its competitors: “The other guys are using aggregators, platforms that were originally developed to sell ring tones and similar goods. Our take is that they won’t be able scale with the volume.”

This is great news for Zong and those of you who enjoy your virtual goods in Facebook games. Follow us on Twitter or Like us on Facebook on our handy new ‘Goose Bar below for future updates on your virtual world.